Moisture in guns and cylinders from filling with either hand pump or compressor

I've been shooting pcp for years and, recently, in the last year or so, have been filling with a GX CS3 ( I also use a CS2 now and again). None of my current batch of eight rifles have been filled by me with anything else. However, some are used, and I have no idea how they were filled. Not knowing the pedigree of these rifles causes me to open them up and make sure there is no moisture in them to cause failure. i have two FX Royales, two HW100's, two Air Arms and a Brocock and a Crosman, as I said, some new, and some used. I am in the process of opening the two FX and Brocock to check them for moisture. Also, I've already opened the two HW's, and found no trace of moisture of any kind.

I had to buy a different wrench setup for the FX and Brocock as they use buddy bottles of CF and one aluminum on my older FX Royale. I ended up buying a Sabre Tactical wrench, clamp wrench and degass tool kit to open the bottles on rifles. I have to tell you, this is without a doubt the BEST way to open these bottles, no slipping, no damage to finish and you can easily remove even the tightest, loctited valve with very little effort. These are fantastically designed tools and I can't recommend them highly enough.

I have now opened the aluminum bottle and found it to be pristine, not a single trace of moisture, pics below. I'm currently in the process of opening all my guns, that aren't new to make sure there's no problems lurking in the depths.

I do run a double set of moisture filters and a third tiny filter with molecular sieve material in the two larger ones, and a cotton filter in the tiny one. This is in addition to the water separator in the CX3. I have recently been aware of some nasty failures of the cheap filter aluminum housings I've been using, so I decided to buy a single, larger filter housing that uses cartridges of molecular sieve, cotton and charcoal in one, which also has wall thicknesses considerably thicker than any of my current filters, and also has a burst disc, just to be on the safe side.

I'm happy that the GX compressors and Hill pumps I've used, have caused no moisture problems at all. I've also been very happy with the GX compressors, they are well built and work like a charm to fill guns, and if I should need parts, they are simply a phone call away.

Here are some pics of my two HW cylinders and my aluminum FX bottle after opening.

IMG_6420.jpg
IMG_6001.JPG
IMG_6004.JPG
 
Well, while I'm not an expert by far, I would guess that since there's no corrosion or deposits, that there is no problem with moisture. I mean, I would think there would be some evidence of it visible.
I also, keep my filters mounted below the bench where my compressor is set up, so that there is a gravity component to the process. Thanks for mentioning that because it is highly important and I had forgot to mention it.

Anyone have any input on the small filter housings that are sold on Amazon? After seeing the failures online, I got a bit worried. I know it's like two or three in several thousand or even hundred thousand, it's still not something I want to mess around with. The longer filter I bought, has considerably thicker walls than those little ones.
 
  • Like
Reactions: iAMzehTOASTY1
I know I've posted this on a few threads, but please check bottles that are 2+ years old ... especially if you used or have used a hand pump.

My Xisico GTX compressor hasn't produced any water in my RAWS. Also, Stainless Steel bottle valves gives superior strength.

The pic below is from my BSA R10 I purchased new in 2015.

BSA Buddy Bottle Break.jpg
 
Last edited:
I know I've posted this on a few threads, but please check bottles that are 2+ years old ... especially if you used or have used a hand pump.

My Xisico GTX compressor hasn't produced any water in my RAWS. Also, Stainless Steel bottle valves gives superior strength.

The pic below is from my BSA R10 I purchased new in 2015.

View attachment 372241
Yeah Ezana,
The brass bottle connection had cracked during a period of time I wasn't shooting the gun much.
I wondered why it would leak a full tank every week, but I was too busy shooting my RAW's to look into it.
Finally, when filling with my compressor, it wouldn't hold air at all.
When I tried to unscrew the bottle, after a moment ..... it simply broke off the gun in my hand o_O.
 
  • Wow
Reactions: Airgun-hobbyist
As an experiment, I tried putting a cylinder of desiccant beads on the intake of my small compressor - these are the "purple beads" that turn pink as they absorb moisture - the housing is clear and it uses simple 1/4 NPT fittings and I just put it in line and filled with beads - the housing has fine particle filters at the top and bottom, so the beads stay in.

Poly tube slip lock fittings and a little poly tube routed out of the compressor case connects the filter housing and the other end of the housing is just open.

This has seemingly worked well - the small aluminum filter post compressor with the cellulose filter would be soaked after filling a 400cc bottle - now its completely dry even filling the 400cc bottle from empty to 300 bar - it doesn't restrict the flow on a small compressor enough to make any difference to the fill time.

These beads can be regenerated by heating - and the color change is noticeable and clear - so far, its working well, is cheap and no high pressure concerns.

Curious if others have experimented with this - I use the same approach for the vents on my vacuum systems so when the vacuum is released, the incoming air is as dry as possible - to reduce pump time and re-cleaning the chamber - and it works there too.

41P-Hl0MlvL._AC_SL1227_.jpg


61Tv7NCGvBL._SL1180_.jpg
 
Companies like Anschutz said hand pumps voided the warranty back in the model 2002CA days. So I was pretty concerned, so I bought a SCBA bottle and had it filled to 4500 psi. That last me a long time, but fills were tough to schedule, and kinda expensive. So I lucked on a Bauer Oceanus compressor, and I think that should be pretty dry. Anyway I feel good with a "alpha" compressor. It cost me 2K, but I think a new one is triple that, so I lie to myself and say 2000 was cheap. Probably cheap if my airguns don't have issues, and they seem rock solid. So I have that in my head.